At present, there is a concern of data traffic increasing in cellular systems due to popularization of smartphones. For this reason, it is increasingly important for cellular service providers to increase communication capacities of the cellular systems.
To increase communication capacities, for example, service providers dispose small cells such as pico cells or femto cells in macro cells. Accordingly, the service provides can obtain new communication capacities. To use such small cells, various examinations have been made.
For example, Non-Patent Literature 1 discloses various disposition scenarios of small cells and use of different frequency bands in macro cells and small cells.